Harnessing automobile energy

Researchers at Ohio State University have invented a new material that may make cars even more efficient by converting heat wasted through engine exhaust into electricity.

The material is claimed to have twice the efficiency of anything currently on the market.

The same technology could work in power generators and heat pumps, said Joseph Heremans, one of the developers of the new material.

The efficiency of thermoelectric materials is based on how much heat they can convert into electricity at a given temperature.

Previously, the most efficient material used commercially in thermoelectric power generators was an alloy called sodium-doped lead telluride, which had a rating of 0.71. The new material, thallium-doped lead telluride, has a rating of 1.5 - more than twice that of the previous leader.

What is more important to Heremans is that the new material is most effective between 450 and 950 degrees Fahrenheit - a typical temperature range for power systems such as automobile engines.